package com.xt.base.wireless.util;
/**
 * Author:杨洪波
 * Date:2014-1-23
 *
 */
public class ByteUtil {
	private static String hexStr =  "0123456789ABCDEF";
	private static String[] binaryArray = 
		{"0000","0001","0010","0011",
		"0100","0101","0110","0111",
		"1000","1001","1010","1011",
		"1100","1101","1110","1111"};
		
	public static void main(String[] args) 
	{
		String str = "二进制与十六进制互转测试==";
		System.out.println("源字符串：\n"+str);
		
		String hexString = binaryToHexString(str.getBytes());
		System.out.println("转换为十六进制：\n"+hexString);
		System.out.println("转换为二进制：\n"+bytes2BinaryStr(str.getBytes()));
		
		byte [] bArray = hexStringToBinary(hexString);
		System.out.println("将str的十六进制文件转换为二进制再转为String：\n"+new String(bArray));
	
	}
	/**
	 * 
	 * @param str
	 * @return 转换为二进制字符串
	 */
	public static String bytes2BinaryStr(byte[] bArray){
		
		String outStr = "";
		int pos = 0;
		for(byte b:bArray){
			//高四位
			pos = (b&0xF0)>>4;
			outStr+=binaryArray[pos];
			//低四位
			pos=b&0x0F;
			outStr+=binaryArray[pos];
		}
		return outStr;
		
	}
	/**
	 * 
	 * @param bytes
	 * @return 将二进制转换为十六进制字符输出
	 */
	public static String binaryToHexString(byte[] bytes){
		
		String result = "";
		String hex = "";
		for(int i=0;i<bytes.length;i++){
			//字节高4位
			hex = String.valueOf(hexStr.charAt((bytes[i]&0xF0)>>4));
			//字节低4位
			hex += String.valueOf(hexStr.charAt(bytes[i]&0x0F));
			result +=hex;
		}
		return result;
	}
	/**
	 * 
	 * @param hexString
	 * @return 将十六进制转换为字节数组
	 */
	public static byte[] hexStringToBinary(String hexString){
		//hexString的长度对2取整，作为bytes的长度
		int len = hexString.length()/2;
		byte[] bytes = new byte[len];
		byte high = 0;//字节高四位
		byte low = 0;//字节低四位

		for(int i=0;i<len;i++){
			 //右移四位得到高位
			 high = (byte)((hexStr.indexOf(hexString.charAt(2*i)))<<4);
			 low = (byte)hexStr.indexOf(hexString.charAt(2*i+1));
			 bytes[i] = (byte) (high|low);//高地位做或运算
		}
		return bytes;
	}
}